Cyber Resilience

CVE-2026-8197

High

Published: 21 May 2026

Published
21 May 2026
Modified
26 May 2026
KEV Added
—
Patch
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CVSS Score v4 7.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0018 7.9th percentile
Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-8197 is a high-severity Cross-site Scripting (CWE-79) vulnerability in Concretecms Concrete Cms. Its CVSS base score is 7.3 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Web Portal Capture (T1056.003); ranked at the 7.9th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

Concrete CMS 9.5.0 and below is vulnerable to Stored XSS via OAuth integration name. The OAuth authorize template renders the integration name (admin-controlled) through Concrete's t() translation helper as a sprintf-style format. The <strong>...</strong> wrap is built by PHP string…

more

interpolation before t() runs, so the integration name lands in the translated output as raw HTML. A rogue admin could potentially snoop on login submissions.The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 7.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N Thanks Yonatan Drori (Tenzai) for reporting.

CWE(s)
CWE-79

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1056.003 Web Portal Capture Collection
Adversaries may install code on externally facing portals, such as a VPN login page, to capture and transmit credentials of users who attempt to log into the service.
attack.mitre.org →
T1185 Browser Session Hijacking Collection
Adversaries may take advantage of security vulnerabilities and inherent functionality in browser software to change content, modify user-behaviors, and intercept information as part of various browser session hijacking techniques.
attack.mitre.org →
Why these techniques?

Stored XSS enables web portal login capture and browser session hijacking via injected scripts.

Confidence: MEDIUM · MITRE ATT&CK Enterprise v18.1

Affected Assets

concretecms
concrete cms
≤ 9.5.0

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

CA-8 Penetration Testing
addresses: CWE-79

Penetration testing submits XSS payloads to web applications, detecting cross-site scripting flaws for subsequent remediation.

SI-10 Information Input Validation
addresses: CWE-79

Validates web inputs to reject script-related content that could produce XSS.

SI-15 Information Output Filtering
addresses: CWE-79

Output validation against expected content can reject or sanitize script content in generated web pages, reducing XSS exploitability.

References